Keep location in router state

Also, clean up unnecessary work in getChildContext

Author: mjackson

modules/LocationUtils.js

@@ -1,5 +1,7 @@
 import { parsePath, createPath } from 'history/PathUtils'
 
+export { locationsAreEqual } from 'history/LocationUtils'
+
 const createRouterLocation = (input, parseQueryString, stringifyQuery) => {
   if (typeof input === 'string') {
     const location = parsePath(input)

modules/StaticRouter.js

@@ -1,7 +1,11 @@
 import React, { PropTypes } from 'react'
 import { stringify, parse as parseQueryString } from 'query-string'
-import { createRouterLocation, createRouterPath } from './LocationUtils'
 import MatchProvider from './MatchProvider'
+import {
+  locationsAreEqual,
+  createRouterLocation,
+  createRouterPath
+} from './LocationUtils'
 import {
   action as actionType,
   location as locationType,
@@ -31,61 +35,83 @@ class StaticRouter extends React.Component {
   }
 
   static defaultProps = {
-    createHref: path => path,
     stringifyQuery,
-    parseQueryString
+    parseQueryString,
+    createHref: path => path
   }
 
   static childContextTypes = {
     router: routerContextType.isRequired,
     location: locationType.isRequired // TODO: Remove location state from context
   }
 
-  createLocationForContext(loc) {
+  createLocation(location) {
     const { parseQueryString, stringifyQuery } = this.props
-    return createRouterLocation(loc, parseQueryString, stringifyQuery)
+    return createRouterLocation(location, parseQueryString, stringifyQuery)
   }
 
-  getChildContext() {
-    const createHref = (to) => {
-      let path = createRouterPath(to, this.props.stringifyQuery)
-      if (this.props.basename) path = this.props.basename + path
-      return this.props.createHref(path)
-    }
+  transitionTo = (location) => {
+    this.props.onPush(this.createLocation(location))
+  }
+
+  replaceWith = (location) => {
+    this.props.onReplace(this.createLocation(location))
+  }
+
+  blockTransitions = (prompt) => {
+    this.props.blockTransitions(prompt)
+  }
 
-    const location = this.getLocation()
+  createHref = (to) => {
+    let path = createRouterPath(to, this.props.stringifyQuery)
+
+    if (this.props.basename)
+      path = this.props.basename + path
+
+    return this.props.createHref(path)
+  }
 
+  getRouterContext() {
     return {
-      location,
-      router: {
-        createHref,
-        transitionTo: (loc) => {
-          this.props.onPush(this.createLocationForContext(loc))
-        },
-        replaceWith: (loc) => {
-          this.props.onReplace(this.createLocationForContext(loc))
-        },
-        blockTransitions: (getPromptMessage) => {
-          this.props.blockTransitions(getPromptMessage)
-        }
-      }
+      transitionTo: this.transitionTo,
+      replaceWith: this.replaceWith,
+      blockTransitions: this.blockTransitions,
+      createHref: this.createHref
     }
   }
 
-  getLocation() {
-    // TODO: maybe memoize this on willReceiveProps to get extreme w/ perf
-    const { location, parseQueryString, stringifyQuery } = this.props
-    return createRouterLocation(location, parseQueryString, stringifyQuery)
+  getChildContext() {
+    return {
+      location: this.state.location, // TODO: Remove location state from context
+      router: this.getRouterContext()
+    }
+  }
+
+  state = {
+    location: null
+  }
+
+  componentWillMount() {
+    this.setState({
+      location: this.createLocation(this.props.location)
+    })
+  }
+
+  componentWillReceiveProps(nextProps) {
+    const nextLocation = this.createLocation(nextProps.location)
+
+    if (!locationsAreEqual(this.state.location, nextLocation))
+      this.setState({ location: nextLocation })
   }
 
   render() {
+    const { location } = this.state
     const { children } = this.props
-    const location = this.getLocation()
 
     return (
       <MatchProvider>
         {typeof children === 'function' ? (
-          children({ location, router: this.getChildContext().router })
+          children({ location, router: this.getRouterContext() })
         ) : (
           React.Children.only(children)
         )}